JPH0329059B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing hydroxydiphenylamines. Hydroxydiphenylamines, especially 4-hydroxydiphenylamine derivatives, are extremely useful compounds as intermediates for organic dyes. Research has been conducted for a long time regarding the synthesis of these compounds, and various methods are known. For example, a method of dehydration condensation of anilines and dihydroxybenzenes (Hemitsier Berichte, Vol. 16, p. 2799),
A method of condensing aminophenols and halogenobenzenes (Hemitsies Zentralbladt, 1907, p. 1465) is known. However, these methods carry out the condensation reaction at a considerably high temperature, resulting in many side reactions and the formation of tar-like substances, resulting in a decrease in yield.Furthermore, they are not economical due to the use of special raw materials. This method has various problems, such as being disadvantageous in terms of production, and cannot be said to be an industrially advantageous method. In particular, when attempting to obtain hydroxydiphenylamines having a halogen group, conventional methods have had the problem that side reactions such as dehalogenation are significant, resulting in extremely low yields and purity. The inventors of the present invention have conducted intensive studies on the method for producing hydroxydiphenylamines, and as a result, have discovered an innovative method for producing hydroxydiphenylamines, which is completely different from conventional methods, and has arrived at the present invention. That is, the present invention is a method for producing hydroxydiphenylamines, which is characterized by diazotizing an aminodiphenylamine compound and then performing a heat treatment in a dilute acid. A feature of the present invention is that the aminodiphenylamine compound is diazotized and then substituted with a hydroxy group. That is, it is a manufacturing method in which an aminodiphenylamine compound is diazotized in a dilute acid, and then the diazonium compound is heat-treated in the dilute acid to produce hydroxydiphenylamines. In the present invention, the diazotization of the aminodiphenylamine compound can be carried out in the cold, preferably at 15° C. or lower, in a dilute acid, preferably 1 to 40% dilute acid. As the dilute acid, inorganic acids other than hydrogen halides, such as sulfuric acid and phosphoric acid, can be used. To replace a diazonium group with a hydroxy group,
The diazonium compound in dilute acid, preferably 1
~30% dilute acid at high temperature, preferably 80-110
At this time, copper compounds such as copper sulfate, copper acetate, copper nitrate,
Salts such as sodium phosphate, toluene, xylene, monochlorobenzene, benzene, nitrobenzene,
Addition of a non-aqueous solution such as dichlorobenzene or decalin is very effective in improving selectivity and yield. The effect is particularly remarkable when a copper compound and a non-water bathing solvent are used together. The copper compounds and salts used at this time are preferably 1 to 50% by weight of the reaction solvent, and the water-insoluble solvent is preferably 3 to 40% by weight. As a method for heat-treating a diazonium compound, a dilute acid solution of a diazonium compound may be heated as it is after adding a copper compound, a salt, or a non-aqueous solvent as the case may be; Alternatively, a dilute acid solution of the diazonium compound may be dropped into water heated to a high temperature to which salts and non-aqueous solvents have been added. According to the present invention, highly pure hydroxydiphenylamines can be obtained with high selectivity and high yield. It is particularly useful for producing hydroxydiphenylamines containing halogen atoms. In the present invention, examples of aminodiphenylamines include the following. 2-chloro-4-aminodiphenylamine, 2
-bromo-4-aminodiphenylamine, 2-methyl-4-aminodiphenylamine, 4-aminodiphenylamine, 2-methoxy-4-aminodiphenylamine, 3-methyl-4-aminodiphenylamine, 3-aminodiphenylamine, 2-
Aminodiphenylamine, 4-amino-4'-methyldiphenylamine, 4-amino-2'-chlorodiphenylamine, 4-amino-3'-methoxydiphenylamine. The present invention will be explained in more detail with reference to Examples below. In the examples, parts and % are parts by weight and % by weight, respectively.
represents. Example 1 21.9 parts of 4-amino-2-chlorodiphenylamine is dispersed in 200 parts of 10% sulfuric acid and diazotized by adding 6.9 parts of sodium sulfite at 15°C or below. Meanwhile, 80 parts of copper sulfate is dissolved in 800 parts of water, 120 parts of toluene is added, and this is heated to 90°C. The diazonium solution was added dropwise to the solution while keeping it at the same temperature. After dropping, keep at the same temperature for 30 minutes,
Then cool to room temperature. Separate the reaction solution by standing and separate it into a toluene layer and a water bath. Toluene in the toluene layer is distilled off, and the remaining reaction product is purified by silica gel column chromatography. 15.4 parts of 4-hydroxy 2-chloro-diphenylamine were obtained.

[Table] Example 2 21.9 parts of 4-amino-2-chlorodiphenylamine is dispersed in 200 parts of 20% sulfuric acid, and diazotized by adding 53.1 parts of a 13°C sodium nitrite solution at 15°C or lower. On the other hand, dissolve 100 parts of copper sulfate in 1000 parts of water, add 150 parts of toluene, and heat this to 90°C. The diazonium solution was added dropwise to the solution while keeping it at the same temperature. After dropping, keep at the same temperature for 30 minutes,
Then cool to room temperature. After the reaction, the mixture is left to stand and dispersed to separate it into a toluene layer and an aqueous layer. The toluene in the toluene layer is distilled off, and the remaining reaction product is distilled under reduced pressure. 14.9 parts of 2-chloro-4-hydroxydiphenylamine were obtained. Distillation temperature: 180-185℃/3mmHg

[Table] Example 3 Disperse 21.9 parts of 4-amino-2-chlorodiphenylamine in 200 parts of sulfuric acid at 15°C, and diazotize by adding 6.9 parts of sodium sulfite at 15°C or below. On the other hand, add 50 parts of copper sulfate, 50 parts of tribasic sodium phosphate, and 100 parts of xylene to 700 parts of water, and heat the mixture at 90°C.
Heat to. The diazonium solution was added dropwise to the solution while keeping it at the same temperature. After dropping, keep at the same temperature for 30 minutes, then cool to room temperature.
Separate the reaction solution by standing to separate it into a xylene layer and an aqueous layer. The xylene in the xylene layer is distilled off, and the remaining reaction product is purified by silica gel column chromatography. 13.5 parts of 4-hydroxy-2-chlorodiphenylamine were obtained.

[Table] Example 4 21.9 parts of 4-amino-2-chlorodiphenylamine was dispersed in 200 parts of 30% phosphoric acid, and the concentration was 13% at 15°C or lower.
Add 53.1 parts of sodium nitrite solution to diazotize. Meanwhile, 100 parts of water, 100 parts of copper sulfate, 300 parts of toluene
of water and heat this to 85°C. The diazonium solution was added dropwise to the solution while keeping it at the same temperature. After cooling to room temperature, the mixture is allowed to stand still and separated into a toluene layer and an aqueous layer. Toluene in the toluene layer is distilled off, and the remaining reaction product is purified by silica gel column chromatography. 12.9 parts of 2-chloro-4-hydroxydiphenylamine were obtained.

【table】

Claims (1)

[Scope of Claims] 1. A method for producing hydroxydiphenylamines, which comprises diazotizing an aminodiphenylamine compound and then heat-treating it in a dilute acid. 2. The method according to claim 1, wherein a copper compound and a non-aqueous solvent are added during the heat treatment in a dilute acid.